I've removed the ancient handsfree cradle in my 2003 Avensis. It was originally installed by a Toyota garage. I've put a DAB+ adapter where it used to be, and plan to power it using the 12 V DC conductors from the handsfree cable.
Then it struck me: What if some of the other conductors could be converted to AUX IN for the car stereo? (That would be way better than the tiny FM transmitter.)
A picture of the phone component is attached. It's labeled BL4041X 09/04, but it doesn't yield any Google results.
So, the question: Does anyone know if there exists a diagram of the conductors, or even if it is possible to create an AUX IN from this?
Update: Having had no luck so far (not even getting 12 V current), I finally removed the necessary panels in the cabin, and found that my previous hypothesis was wrong. The other end is some proprietary 15 pin D-sub, and it connects into a box behind the glove compartment.
Left to right: the D-sub connenctor, a 2.5 mm jack for the microphone, 4 pin connector (sound?), 4 pin connector (power?)
I think this should simplify my project. Now I can simply remove that box, and just use those standard connectors instead. I'll post an answer as soon as I've been able to complete it. In the meantime, if anyone recognizes those 4 pin cables, I'll be happy to receive a link to a wiring diagram. I suspect it will make everything go a little bit quicker.